NBA Hall of Famer and Celtics legend Kevin McHale is mourning his daughter who died Saturday.

Alexandra “Sasha” McHale, the daughter of NBA Hall of Famer and Celtics legend Kevin McHale died Saturday due to complications from lupus, an auto-immune disease, according to multiple reports. McHale was part of the Celtics original “Big Three” and helped lead the team to five NBA Finals appearances in the 1980s. His number, 32, is retired at the Garden, and for those of us that grew up in that era, he is remembered to be part of one of the best (if not, the best) front lines in NBA history (with Larry Bird and Robert Parrish). He is currently the head coach of the Houston Rockets and has been on personal leave since November 10th, when his daughter was hospitalized with a lupus-related condition.

According to the U.S. National Library of Medicine, lupus is an autoimmune disease, which means the body’s immune system mistakenly attacks healthy tissue. This can lead to long-term (chronic) inflammation. Dr. Elinor A. Mody, director of the Women’s Orthopedic and Joint Disease Program at Brigham and Women’s Hospital says that lupus is a rare disease, and severe lupus is even more rare. Mody says that major complications from lupus can affect the kidneys, central nervous system, bone marrow, and the lungs.

While the exact details surrounding McHale’s case are not yet known, Mody says that there are a number of ways someone so young can die of lupus complications. “Many of the lupus patients who die, die of infection from the immunosuppressive drugs that we use to treat the disease, in particular corticosteroids,” Mody says. “Rarely, patients with lupus can die of a condition called shrinking lung. Lupus patients also get accelerated cardiac disease, which can cause death by heart attack, or abnormal heart rhythms.”

According to the Mayo Clinic, lupus can be difficult to diagnose because its signs and symptoms often mimic those of other ailments. While there is no cure, there are treatment options available. Mody says that new treatments and advancements are being studied. “There is help available, treatments available, so if there is concern that someone has lupus, it is very important to seek medical attention,” Mody says.